The United States is the world-wide leader in corn (maize) production, producing about twice as much corn as the second-ranked producer. By far, corn is the most important grain crop in the United States. According to USDA estimates, corn ranked first in 1998 in acreage accounting for 24 percent of all crop acres in the United States. Nearly twice as many bushels of corn are produced per year in the U.S. than are produced for any other grain crop.
Despite the large amount of corn produced in the United States, only a minor portion of this corn is used directly for human consumption. The impact of corn on the American diet, however, is certainly not insignificant. Indirectly, corn has a profound impact on the American diet. Because the majority of the United States corn crop is used as feed for livestock, much of the meat consumed in the United States comes from animals that have been fed a diet that includes corn. In addition, corn also impacts the American diet in products that are come from the processing or refining of corn kernels. Key among the food products derived from corn refining are starch, corn oil and corn syrup. Produced from the hydrolysis of starch, corn syrup is used primarily as a sweetener, often replacing cane sugar (sucrose) in food and beverage products. While a variety of corn syrups may be produced from corn starch, the most popular form for use as a sweetener is high-fructose corn syrup. Over the last decade, high-fructose corn syrup has become the favored sweetener for many food products including most of the leading soft drinks.
Because of the importance of corn, plant breeders and other agricultural scientists have focused a great deal of their efforts on improving corn germplasm. While traditional efforts to improve corn have provided cultivars with improved yield potential and enhanced disease resistance, new approaches involving genetic engineering have already proven successful and have provided the corn producer new varieties with increased resistance to herbicides and insects. Other corn improvement efforts have focused on improving grain quality traits such as amino acid content, starch composition, oil content and composition, phytate content, and characteristics which affect corn refining processes such as wet milling. While traditional plant breeding approaches will continue to be relied upon for corn improvement, genetic engineering promises to provide novel approaches that can increase the rate of new cultivar development.